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Established 2004

Ruddlesden geotechnical

Ruddlesden geotechnical provides ground investigation, geotechnical consultancy and contamination assessment services.

Based in Exeter, but covering the whole of the UK, albeit primarily concentrated in the South West, Ruddlesden geotechnical was formed in 2004.

Ruddlesden geotechnical works on behalf of a wide client base, including local, regional and national housing developers, housing associations, commercial developers, building contractors, structural and civil engineers, architects, building consultants, quantity surveyors, local authorities and private individuals.

Development projects range from single dwellings and extensions to large housing estates, multi-storey flats, offices, industrial units, roads, slopes, schools, hospitals and basements.

The services and projects listed on this web-site provide an indication of those undertaken by Ruddlesden geotechnical, but others are carried out. If your requirement is not readily identifiable on this web-site, please contact us as we may still be able to help you.

  • AGS
  • Constructionline
  • CSCS
  • SMAS
  • ECFC trust

Latest news

Recent projects

  • Latest news

    25 Mar 2026

    BRE 365 Soakaway Testing

    Simon Ruddlesden was pleased to present at the AGS Annual Conference, to talk about BRE 365 soakaway testing, asking the question, though not necessarily providing the answer: Should we be carrying out BRE 365 soakaway testing in geologies where previous testing has shown soakaway/ infiltration drainage to be unsuitable? The BRE 365 soakaway test is widely accepted and requested as the field test that is to be carried out to assess the suitability of the ground for soakaway/ infiltration drainage. However, the test is not without danger, mainly due to working at height risks, and it is relatively wasteful of resources, including fuel and water. If previous testing results consistently and convincingly show that certain geologies are unsuitable for soakaway/ infiltration drainage, should a relatively unsafe and not particularly sustainable test be carried out? Using data from over 5,000 tests on more than 1,200 sites investigated by Ruddlesden geotechnical over the last 20 years, mainly in the South West, there is a clear and understandable correlation between unsuccessful tests and the underlying geology, where the underlying geology comprises predominantly lower permeability mudstones and clays, notably the Mercia Mudstone Group, Lias Group and Oxford Clay Formation, although there are a number of anomalies, which can usually be explained by a closer inspection of the local geology, including superficial deposits. More data and research will be required if regulators and designers are to accept that no testing is required in certain geologies. The presentation sparked an interesting discussion afterwards, and it is hoped that it will have inspired others to share their data and/ or offer technical support, to ultimately produce a map that provides confidence to regulators and designers that BRE 365 testing is not required in certain geologies. Please contact us directly if you would like to discuss this further.

    BRE 365 Soakaway Testing
    BRE 365 Soakaway Testing

  • Recent projects

    Multiple Ground Investigation Techniques on Site in Cornwall

    A combination of trial pits and dynamic sampling (windowless sample boreholes)with in-situ and laboratory testing has been undertaken as part of an ongoing ground investigation for a large residential development on the outskirts of Newquay, in Cornwall. The trial pits have allowed in-situ soakaway testing to be undertaken in accordance with BRE DG 365, to provide information for surface water drainage design. The boreholes have allowed in-situ standard penetration testing (SPTs) to be carried out, to provide information for foundation and retaining wall design. The boreholes have also been used to install monitoring wells for long-term gas monitoring. Both the trial pits and boreholes have been used to obtain representative samples for both contamination and geotechnical assessment purposes, which has included earthworks testing for the re-use of site-won soils. Ruddlesden geotechnical’s knowledge of the ground conditions on this site has enabled the most suitable and cost-effective method of investigation to be used.

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  • Recent projects

    Foundations Options Appraisal, Somerset

    The Somerset Levels typically comprise a thick sequence of Quaternary and Recent Alluvium/ Tidal Flat Deposits, made up of layers of peat, clay, silt, sand and gravel, underlain by Triassic and Jurassic bedrock deposits. The cost-effective development of residential housing can be difficult in this area of the country, due to the deep Alluvium/ Tidal Flat Deposits, often ranging between 10m and >20m in thickness, which sometimes results in piled foundations being the default foundation solution, which can often affect the viability of the project. The upper 1.5m-2.0m of the Alluvium/ Tidal Flat Deposits often comprise desiccated clay soils and can, in some circumstances, provide a suitable founding stratum for shallow foundations. Conversely, for larger developments, ground improvement can also be considered to facilitate the use of shallow foundations, as a cost-effective alternative to piles. As part of a general ground investigation, Ruddlesden geotechnical have recently undertaken a foundation options appraisal in Weston-super-Mare for a proposed residential development, where all of the above were considered, to provide the most cost-effective solution for the developer. A mix of piled and strip/ trench-fill foundations were recommended, directly relating to the underlying geology.

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